Start here: https://support.mozilla.org/en-US/kb/cannot-receive-messages and if that doesn't help, tell us whether you use IMAP or POP, and who your email provider is (e.g. gmail).

Thanks for the link, duggabe but I'm still no closer.

I'm using IMAP and SMTP for my e-mail, as provided by Gandi.net[1]. The settings work for my non-Thunderbird based clients or webmail.

[1]: http://wiki.gandi.net/en/mail/standard-settings

Here are a few things to try:

• Make sure you are using your full email address in Server Settings -> User Name
• try port 993 instead of 143
• Help -> Restart with Add-ons Disabled
• can you send an email?

Have you gone through gandi's troubleshooting steps?

I'm using the server settings of mail.gandi.net with port 993 (for IMAP) and port 465 for SMTP. I've spoken with Gandi and they told me it's a problem with my mail client, Thunderbird.

I'm unable to either send or receive e-mails from that account but can do so from another account, also with Gandi with the same settings apart from username which is that mailboxes e-mail address.

The only add-ons I have for Thunderbird are the British English dictionary and the chat messenger installed as standard (but I never use it).

Start a terminal window and enter "ping mail.gandi.net" (without the quotes). You should get repeated responses. Control-C to stop it.

try port 143 instead of 993. try port 587 instead of 465 did you restart without add-ons?

Thanks for the update. ping -c 5 mail.gandi.net returned 0% packet loss (I can access it through Firefox). I did restart it with the add-ons disabled to no avail.

I tried changing the ports to those you mentioned but the system seemed to be stuck as it was taking an absolute age to do nothing. I was keeping an eye on the network activity at the same time. When I used the port numbers you sugested I got no error message at all but when I changed them back I got the same error as earlier.

Einherjar said

I'm using the server settings of mail.gandi.net with port 993 (for IMAP) and port 465 for SMTP. I've spoken with Gandi and they told me it's a problem with my mail client, Thunderbird. I'm unable to either send or receive e-mails from that account but can do so from another account, also with Gandi with the same settings apart from username which is that mailboxes e-mail address.

If you have another account with gandi which works with TB, and you have replicated those settings, then it seems you need to verify your account name and get them to change your password. I don't see how TB could work for one account and not another with the same settings and the same provider.